A Brief Look at Metalworking Processes

Metalworking has been around since ancient times but thanks to modern technology it has become quite a prolific industry. And this technology allows for metal shaping and metalworking—a process collectively known as metallurgy—in many different ways.

Dcmgroup.ca works with companies that shape metals through a wide variety of methods. This includes:

Casting—pouring molten metal into a shaped mold

Forging—hammering a red-hot billet into a specific shape

Rolling—pass a billet through a series of progressively narrower rollers to create a sheet

Laser cladding—blowing metallic powder through a movable laser into a substrate, which forms a melt pool; moving the laser head can stack these tracks to form a three-dimensional object

Extrusion—forcing hot and malleable metal through a die, using great pressure, forming a shape as the metal cools

Sintering—heating a powdered metal in a non-oxidizing environment after die compression (from extrusion)

Machining—using mills, drills, or lathes to cut cold metal into a shape

Fabrication—cutting sheets of metal with gas cutters or guillotines and then bending and welding into structural shapes

3D printing—using sintering or melting of amorphous powdered metal in a 3D space to make a particular shape or object

Heat Treatments

The treatment of metals using heat is a common metallurgical practice. Heat, of course, alters the properties of metal, generally reducing characteristics like strength, hardness, and ductility. It can also change the resistance to corrosion (by increasing or reducing it). Common heat treatments include:

Annealing—softening metals by heating and then slow-cooling to reduce stresses in the metal and make the grain structure large

Quenching—rapid cooling of high-carbon steel after heating to “freeze” the steel molecules

Tempering—heating to relieve stresses caused in the hardening process

Non-Heating Treatments

Some metal treatments do not involve heat. These include:

[Electro]Plating—This is a process which involves bonding a thin layer of one metal, often chromium, gold, silver, or zinc, to the surface of another product.

Shot peening—a cold metalworking process used in the finishing of metal parts; characterized by a small, round shot blasted against the surface of the part that needs finishing

Thermal spraying—also a finishing option, this simply involves the industrial spray welding process which uses a heat source to melt a coating material on the surface of whatever material to be treated. This is known by many names (HVOF, flame spray, metalizing, plasma spray, and arc spray).